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From: Jaroslav Kysela <perex@suse.cz>
To: Junfeng Yang <yjf@stanford.edu>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"mc@cs.stanford.edu" <mc@cs.stanford.edu>
Subject: Re: [CHECKER] potential dereference of user pointer errors
Date: Mon, 24 Mar 2003 10:07:07 +0100 (CET)	[thread overview]
Message-ID: <Pine.LNX.4.44.0303241004100.1189-100000@pnote.perex-int.cz> (raw)
In-Reply-To: <Pine.GSO.4.44.0303231506070.21702-100000@elaine24.Stanford.EDU>

On Sun, 23 Mar 2003, Junfeng Yang wrote:

> ---------------------------------------------------------
> [BUG] snd_sb_csp_ioctl -> snd_sb_csp_riff_load ->snd_sb_csp_load.
> /home/junfeng/linux-2.5.63/sound/isa/sb/sb16_csp.c:647:snd_sb_csp_load:
> ERROR:tainted:647:647:deferencing buf++ tainted by
> [dist=-1][(null)][TRANS: buf++, $stop$->tainted,
> /home/junfeng/linux-2.5.63/sound/isa/sb/sb16_csp.c, snd_sb_csp_load, 647]
> 
> 		}
> 		kfree (_kbuf);
> 	} else {
> 		/* load from kernel space */
> 		while (size--) {
> 
> Error --->
> 			if (!snd_sbdsp_command(p->chip, *buf++))
> 				goto __fail;
> 		}
> 	}

This code is ok. The source (user or kernel space) is checked a few lines 
before.

> ---------------------------------------------------------
> [BUG] copy function can take tainted inputs
> /home/junfeng/linux-2.5.63/sound/pci/es1938.c:833:snd_es1938_capture_copy:
> ERROR:tainted:835:833: passing dst into deref cal __constant_memcpy
> [dist=1][thru snd_pcm_ops_t:copy
> /home/junfeng/linux-2.5.63/sound/pci/cmipci.c:snd_cmipci_ac3_copy:parm3
> copy_from_user:parm1][START: dst, unknown->tainted,
> /home/junfeng/linux-2.5.63/sound/pci/es1938.c, snd_es1938_capture_copy,
> 833]
> 
> 	es1938_t *chip = snd_pcm_substream_chip(substream);
> 	pos <<= chip->dma1_shift;
> 	count <<= chip->dma1_shift;
> 	snd_assert(pos + count <= chip->dma1_size, return -EINVAL);
> 	if (pos + count < chip->dma1_size)
> Error --->
> 		memcpy(dst, runtime->dma_area + pos + 1, count);
> 	else {
> Start --->
> 		memcpy(dst, runtime->dma_area + pos + 1, count - 1);
> 		((unsigned char *)dst)[count - 1] = runtime->dma_area[0];
> 	}
> 	return 0;

Fixed. Replaced memcpy with copy_to_user(). Thanks.

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs


  parent reply	other threads:[~2003-03-24  8:56 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-03-04 11:12 [CHECKER] potential races in kernel/*.c mm/*.c net/*ipv4*.c Dawson Engler
2003-03-04 12:24 ` Hugh Dickins
2003-03-04 13:23 ` Martin Josefsson
2003-03-21  6:33 ` [CHECKER] potential dereference of user pointer errors Junfeng Yang
2003-03-21 21:44   ` Chris Wright
2003-03-21 21:58     ` Junfeng Yang
2003-03-21 22:06       ` Chris Wright
2003-03-21 22:08     ` Junfeng Yang
2003-03-21 22:15   ` Chris Wright
2003-03-22 20:49     ` Alan Cox
2003-03-22 20:19       ` Chris Wright
2003-03-21 23:55   ` Chris Wright
2003-03-27  8:07     ` Jan Kasprzak
2003-03-27 17:10       ` Chris Wright
2003-04-21  7:49         ` [CHECKER] Help Needed! Junfeng Yang
2003-04-21 21:26           ` Chris Wright
2003-04-26  2:18             ` [CHECKER] 30 potential dereference of user-pointer errors Junfeng Yang
2003-04-27  9:26               ` James Morris
2003-04-28  1:55                 ` Junfeng Yang
2003-04-27 20:18               ` Nick Holloway
2003-04-27 21:14                 ` Junfeng Yang
2003-04-27 21:29               ` Junfeng Yang
2003-04-28  6:43               ` [CHECKER] 3 potential user-pointer errors in drivers/usb/serial that can print out arbitrary kernel data Junfeng Yang
2003-04-29  7:25                 ` Greg KH
2003-04-29  9:14                   ` Junfeng Yang
2003-04-28  6:50               ` [CHECKER] 8 potential user-pointer errors that allow arbitrary writes to kernel Junfeng Yang
2003-04-28 12:49                 ` Alan Cox
2003-04-28 19:11                   ` Junfeng Yang
2003-04-29  0:02                     ` [CHECKER] 5 potential user-pointer errors in write_proc Junfeng Yang
2003-04-29  7:26               ` [CHECKER] 30 potential dereference of user-pointer errors Greg KH
2003-03-22  0:15   ` [CHECKER] potential dereference of user pointer errors Chris Wright
2003-03-22  0:32     ` Greg KH
2003-03-22  0:47       ` Chris Wright
2003-03-22  1:00         ` Greg KH
2003-03-22  0:32   ` Chris Wright
2003-03-23 23:10   ` Junfeng Yang
2003-03-24  0:24     ` [CHECKER] 63 potential calling blocking functions with locks held errors Junfeng Yang
2003-03-24 12:35       ` [CHECKER] 8 potential calling blocking kmalloc(GFP_KERNEL) " Junfeng Yang
2003-03-24  0:29     ` [CHECKER] 1 potential double unlock error Junfeng Yang
2003-03-24  9:07     ` Jaroslav Kysela [this message]
2003-03-24 22:28   ` [CHECKER] potential dereference of user pointer errors Raja R Harinath
2003-03-25  0:44     ` David S. Miller
2003-03-25 18:52       ` Raja R Harinath

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